Search found 37 matches

by Jonathan Shih 3H
Mon Mar 07, 2016 6:03 am
Forum: *Cycloalkanes
Topic: cycloalkanes vs alkenes
Replies: 2
Views: 354

Re: cycloalkanes vs alkenes

If given the chemical formula, any double or triple bonds would be indicated. So rather than CH3CH3 it would be CH3=CH3 for a double bond. With that being said, yes it does matter if you draw one over the other, as you would draw a cycloalkane if there were only single bonds and an alkene if there w...
by Jonathan Shih 3H
Fri Mar 04, 2016 7:15 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Relieving Torsional Strain
Replies: 1
Views: 279

Relieving Torsional Strain

Recalling wednesday's lecture, Dr. Lavelle described relieving torsional strain by rotation. First of all, just to make sure, the strain is caused by the eclipsed conformation right? And to relieve said strain, the rotation Dr. Lavelle was talking about would be the rotation to go from a Eclipsed co...
by Jonathan Shih 3H
Sun Feb 28, 2016 11:39 am
Forum: *Alkenes
Topic: Benzene vs Phenyl
Replies: 2
Views: 394

Re: Benzene vs Phenyl

Hey, Benzene refers to a specific ring molecule C6H6 with alternating double and single molecules, where as Phenyl refers to the category of functinal groups that essentially looks like benzene, but instead of being actual benzene, one of the hydrogens is replaced with a bond to the parent molecule/...
by Jonathan Shih 3H
Sun Feb 28, 2016 11:33 am
Forum: *Cyclopropanes and Cyclobutanes
Topic: Bond Angle Strain vs. Torsional Strain
Replies: 8
Views: 1305

Re: Bond Angle Strain vs. Torsional Strain

Hey, I'm not sure we need to know this distinction since it seems like this is 14C material, but here's a UCLA resource (I think it's actually from Hardinger's class) that could help clarify the distinction between the two types of strains. http://www.chem.ucla.edu/harding/notes/strain_02.pdf"onclic...
by Jonathan Shih 3H
Sun Feb 28, 2016 11:22 am
Forum: *Alkanes
Topic: Quiz 3 preparation: practice quiz 1.2--possible error?
Replies: 1
Views: 250

Re: Quiz 3 preparation: practice quiz 1.2--possible error?

Hey,
Really lackluster response, but simply, yes, I agree with you! The ethyl should come before the (tri)methyl. Or in any case, the ethyl should always come before the methyl in terms of the naming.
by Jonathan Shih 3H
Wed Feb 17, 2016 3:54 pm
Forum: General Rate Laws
Topic: Stoichiometric coefficients and rate laws
Replies: 1
Views: 402

Re: Stoichiometric coefficients and rate laws

I don't think the stoichiometric coefficients are very important in determining the order of the reaction; I think you just compare the rates based on changes in the concentrations. This is because when you're comparing rates, the rates themselves already incorporate the stoichiometric coefficients,...
by Jonathan Shih 3H
Mon Feb 15, 2016 9:19 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Activation Energy and Temperature
Replies: 1
Views: 338

Re: Activation Energy and Temperature

Technically, there is no relationship between temperature and activation energy, the temperature doesn't affect the amount of activation energy that is need for the reaction to occur. However, when you start off at a higher temperature, the reactants naturally start of with more energy (temperature ...
by Jonathan Shih 3H
Mon Feb 15, 2016 9:14 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: What affects reaction rates?
Replies: 2
Views: 373

Re: What affects reaction rates?

There are many factors that can affect reaction rates, such as concentration of the reactants, the temperature in which the reaction takes place, and the phase and surface area of the reactants at the time the reaction takes place(which I don't think we need to account for/worry about).
by Jonathan Shih 3H
Sat Feb 06, 2016 8:05 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Midterm 2011 2B
Replies: 2
Views: 476

Re: Midterm 2011 2B

Hey! My TA actually warned me about this earlier and I think I can help! Basically, the problem is being tricky here, where it is stating that there is 1mol of the element, and that element is in the form of a monatomic or diatomic gas. This means that for the diatomic gas, there are essentially hal...
by Jonathan Shih 3H
Sat Jan 30, 2016 11:45 pm
Forum: Balancing Redox Reactions
Topic: Redox reactions in Basic or Acidic conditions
Replies: 3
Views: 1566

Re: Redox reactions in Basic or Acidic conditions

you should be told if the reaction is in an acid or a base.
by Jonathan Shih 3H
Sat Jan 30, 2016 6:23 pm
Forum: Balancing Redox Reactions
Topic: Redox reactions in Basic or Acidic conditions
Replies: 3
Views: 1566

Re: Redox reactions in Basic or Acidic conditions

Hi there! So the only difference between reactions in basic and acidic conditions is that blaancing reactions in a base, you would first balance it like how you would in an acid, but since you're in a basic solution now, you would add enough OH- to both sides of the equation to neutralize the H+. So...
by Jonathan Shih 3H
Wed Jan 27, 2016 3:32 am
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: ΔU=0 in Isothermal Process
Replies: 1
Views: 473

Re: ΔU=0 in Isothermal Process

As Dr. Lavelle addressed in class, looking at your question strictly mathematically, recall that delta U, change in internal energy, is also equal to 3/2nRdeltaT. So when the process is isothermal, indicating no change in T and therefore a delta T of 0, then essentially we have delta U=3/2nR(0), whi...
by Jonathan Shih 3H
Wed Jan 27, 2016 3:24 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Specific Heat Sig Figs
Replies: 1
Views: 1080

Re: Specific Heat Sig Figs

I think that although it is a pre-determined valued, these given values have probably been tested and calculated the many more sig figs, however, what we are given are usually the values rounded to a certain number of sig figs. Therefore, I do think that we have to do account for sig figs in Specifi...
by Jonathan Shih 3H
Sun Jan 17, 2016 3:39 pm
Forum: Phase Changes & Related Calculations
Topic: Isolated Systems
Replies: 2
Views: 314

Re: Isolated Systems

That's because no heat nor any matter is being lost or added to the system. This is described the law of conservation of energy, which states that the total energy of an isolated system is constant. Although energy can change forms, an example being mechanical to thermal, it can't be created nor des...
by Jonathan Shih 3H
Sun Jan 17, 2016 3:24 pm
Forum: Phase Changes & Related Calculations
Topic: Systems at constant pressure
Replies: 1
Views: 300

Re: Systems at constant pressure

I don't think it matters if the internal pressure is equal to the outside pressue, all that matters is that when it says pressure is constant it means that for the system that you're working with, the pressure of that system is constant. Atleast I think that's the only thing you can assume from that...
by Jonathan Shih 3H
Sun Jan 10, 2016 9:48 pm
Forum: Phase Changes & Related Calculations
Topic: Change in Enthalpy from Reactants to Products
Replies: 1
Views: 237

Re: Change in Enthalpy from Reactants to Products

There are three ways: 1. Using Hess's law and using the standard change in enthalpies for different but similar reaction and using substitution and such like shown in the course reader example, we can find the change of enthalpy for the specific reaction we're looking for. 2. We can look at individu...
by Jonathan Shih 3H
Fri Dec 04, 2015 4:10 pm
Forum: *Making Buffers & Calculating Buffer pH (Henderson-Hasselbalch Equation)
Topic: Henderson-Hasselbach Equation
Replies: 3
Views: 741

Re: Henderson-Hasselbach Equation

I'm glad it did! To explain further: You know when it's a buffer when it's a weak acid and it's conjugate base or when it's a weak base and it's conjugate acid. I thinkt here's more clarification on page 156 of the course reader, where it's explained what a buffer is and actually uses the Henderson ...
by Jonathan Shih 3H
Fri Dec 04, 2015 7:23 am
Forum: *Making Buffers & Calculating Buffer pH (Henderson-Hasselbalch Equation)
Topic: Henderson-Hasselbach Equation
Replies: 3
Views: 741

Re: Henderson-Hasselbach Equation

I don't the knowing the derivation of the equation is very important, but it is very important that you know when to use it. In most acid-base reactions, we would typically just calculate what we need using ICE boxes. However, to get the pH of buffer solutions, we use the Henderson Hasselbach (if yo...
by Jonathan Shih 3H
Mon Nov 30, 2015 3:11 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Acid strength-HClO4 vs H3PO4 (HW 12.51d)
Replies: 2
Views: 2536

Re: Acid strength-HClO4 vs H3PO4 (HW 12.51d)

In this case, I think you just have to know that perchloric acid is a strong acid so it dissociates completely in an aqueous solution while phosporic acid simply does not as it is a weak acid. Sorry if I can't come up with a better explanation but I think this one of those more black and white answe...
by Jonathan Shih 3H
Mon Nov 30, 2015 3:01 am
Forum: Polyprotic Acids & Bases
Topic: How to identify a polyprotic acid/base
Replies: 1
Views: 4124

Re: How to identify a polyprotic acid/base

I don't think there's a general trend that we need to known regarding which elements can form polyprotic acids/bases. However, I think the rather we should just be familiar with the common ones, some being: http://wps.prenhall.com/wps/media/objects/3312/3392119/imag1606/TB16_003.GIF As for the secon...
by Jonathan Shih 3H
Sun Nov 22, 2015 10:20 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: new initial for an ICE box
Replies: 1
Views: 256

Re: new initial for an ICE box

Essentially, what they were trying to accomplish was removing a "number - x" and instead just having an "x" from the equilibrium calculations. They did so by shifting the equation left to favor the reactants, so it consumed the only mole of H2 and also one mole of CI2 (done by lo...
by Jonathan Shih 3H
Sun Nov 22, 2015 10:14 pm
Forum: Ideal Gases
Topic: When is K small enough to make the assumption
Replies: 2
Views: 497

Re: When is K small enough to make the assumption

Ok, in high school I learned that 10^-4 and greater is ok to make the assumption because when you work the problem out with sig figs, the number itself is enough doesn't have an impact on the final rounded number. However, I asked my TA, Andy Smaligo, just to make sure and he said that for the the p...
by Jonathan Shih 3H
Sun Nov 22, 2015 10:11 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Partial Pressures
Replies: 1
Views: 316

Re: Partial Pressures

From my experience doing all the homework problems, I think either one is ok. Just make sure you use the right gas constant if you're using PV=NRT to convert from moles per liter to pressure.
by Jonathan Shih 3H
Mon Nov 16, 2015 3:42 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: question on 11.55
Replies: 3
Views: 397

Re: question on 11.55

Sorry, perhaps it was due to my typo within the question, but I was asking about functions with a cubic power and higher, such as this question, which involves a power of 5.
by Jonathan Shih 3H
Mon Nov 16, 2015 4:32 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: question on 11.55
Replies: 3
Views: 397

question on 11.55

For question 11.5, to solve for the equilibrium concentrations I believe we need a graphing calculator, however are we allowed to use graphing calculators for the upcoming quiz?
by Jonathan Shih 3H
Sun Nov 15, 2015 7:04 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Favorable physical conditions
Replies: 1
Views: 337

Re: Favorable physical conditions

Hi there! Given the equation already at a state of equilibrium, you essentially look at any change in pressure when looking at how the equilibrium would shift at different conditions. If pressure within the closed environment/container increased, the equation would shift to produce the molecule rath...
by Jonathan Shih 3H
Tue Nov 10, 2015 2:55 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Small Amount of K
Replies: 2
Views: 257

Re: Small Amount of K

Hi! I'm slightly confused as to what you're specifically asking, but I hope I can clarify and add some explanation as to the whole "x" variabe and how we can assume that it's essentially 0. We use a general variable "x" because honestly, it doesn't matter what variable we pick, a...
by Jonathan Shih 3H
Mon Nov 02, 2015 9:28 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Drawing Heteronuclear MO diagrams
Replies: 1
Views: 252

Drawing Heteronuclear MO diagrams

When drawing these diagrams, is it enough just to make sure than the more electronegative atom's orbitals are drawn visibly lower than the other atom's orbitals? Or are there any other specifications, like if one has to be drawn a specific distnace lower?
by Jonathan Shih 3H
Mon Nov 02, 2015 9:17 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: H-F Diagram
Replies: 4
Views: 1324

Re: H-F Diagram

I thought that we had to know how to do them, weren't heteronuclear MO diagrams covered in Friday's lecture? I'm pretty sure that they aren't too much different from homonuclear diatomic molecules though, just that the atomic orbitals of the atom with a higher electronegativity needs to be drawn vis...
by Jonathan Shih 3H
Sun Nov 01, 2015 1:59 am
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Ionization Energy
Replies: 1
Views: 253

Re: Ionization Energy

If you think of this answer in terms of the atomic diagram, the the further away the electron is from the nucleus, the easier it is to remove it from the atom. Therefore, when it is in a higher molecular orbital, it is farther from the positive nucleus (repelled further by the electrons other than t...
by Jonathan Shih 3H
Sun Nov 01, 2015 1:49 am
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: H-F Diagram
Replies: 4
Views: 1324

Re: H-F Diagram

Here it is attached in the image!Image
by Jonathan Shih 3H
Mon Oct 26, 2015 12:05 am
Forum: Bond Lengths & Energies
Topic: Solution Manual Typo for 3.89 b
Replies: 1
Views: 362

Solution Manual Typo for 3.89 b

I think I see a typo for question 3.89 in the explanation for part b as to why the bond length between carbon and nitrogen is 142 rather than 152. The sentence reads as "However, because the C atom is involved in *page break* pm), and the N single bond radius gives 142, which is close to the ex...
by Jonathan Shih 3H
Sun Oct 25, 2015 10:57 pm
Forum: Dipole Moments
Topic: "Polarizing Power" Trends
Replies: 1
Views: 606

"Polarizing Power" Trends

What are the trends for polarizing power? From question 81 in Chapter 3, I inferred that for cations, the smaller the Cation, the greater the polarizing power. Is it the same for Anions?
by Jonathan Shih 3H
Mon Oct 19, 2015 1:15 am
Forum: Resonance Structures
Topic: Resonance hybrids of covalent and ionic structures
Replies: 1
Views: 390

Re: Resonance hybrids of covalent and ionic structures

I think based on what Dr. Lavelle explained in the lecture, it's based on whether there are double or triple bonds. I think the part of the structure with the double or triple bond contributes more to the resonance.
by Jonathan Shih 3H
Mon Oct 19, 2015 1:03 am
Forum: Ionic & Covalent Bonds
Topic: Ground State Electron Configuration for Ions
Replies: 3
Views: 775

Re: Ground State Electron Configuration for Ions

Honestly, it shouldn't matter what version you put. Either shows your understanding of the number of electrons after being ionized.
by Jonathan Shih 3H
Sun Oct 11, 2015 2:25 pm
Forum: Properties of Light
Topic: How to increase the intensity of the photon
Replies: 6
Views: 883

Re: How to increase the intensity of the photon

As Dr. Lavelle said, the intensity is directly proportional to the number of electrons, so you can't increase the intensity, but rather you increase the intensity of the light ray by increasing the number of photons. Also, in your initial statement before your question, isn't the opposite true? Once...
by Jonathan Shih 3H
Sat Oct 03, 2015 2:03 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7832
Views: 1088443

Re: Chemistry Jokes

If H20 is water, what is H204?
Drinking, bathing, washing, swimming, etc.

If H2O is the formula for water, what is the formula for ice?
H2O cubed.

Anyone know any jokes about the element sodium?
Na.

Go to advanced search